/*
 * Copyright 2009 XueSong Guo.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.webwheel.database.annotations;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * declare a setter method is outer join.<br/>
 * that means the object set maybe null value.<br/>
 * <code><b>example:</b>
 * <pre>
 * create table one(id int);
 * create table many(id int, oneid int references one(id));
 * public interface Query {
 *   {@code @}Table("one")
 *   {@code @}Select("select * from one left outer join many on one.id=many.oneid")
 *   {@code @}OuterJoin
 *   public List&lt;One&gt; getOneList();
 *
 *   {@code @}Table("many")
 *   {@code @}Select("select * from many left outer join one on many.oneid=one.id")
 *   {@code @}OuterJoin
 *   public List&lt;Many&gt; getManyList();
 * }
 * </pre></code>
 * because in this one-to-many relation, either side maybe null, the annotation OuterJoin must be used.
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface OuterJoin {
}
